Value of Underwater Habitats Ecosystem Services

Within this research project, methods were developed to describe the value and magnitude of chosen marine ecosystem services. The aim was to enable the integration of ecosystem services into political decisions, and in the end contribute to a sustainable management of the coastal zone. The value of ecosystem services provided by two separate but complementary study systems were assessed: shallow fish reproduction habitats and deep sediment habitats.

The marine environment generates a large number of ecosystem services. The coastal zone provides essential habitats for a large part of the economically most important fish species. Also, vegetated areas along the coast bind sediments and nutrients, thus protecting the open sea. Simultaneously, the dense human populations along the coasts put high, and accelerating, pressure on the coastal ecosystem through overexploitation, habitat transformation and pollution, threatening the valuable ecosystem services provided by these shallow-water habitats.

Aphotic soft substrate sediments cover approximately 90% of the Baltic Sea seafloor and provide crucial ecosystem functions such as decomposition of organic matter and re-mineralization of nutrients. The processes are influenced by the benthic fauna, which decompose and bury matter that otherwise would contribute to eutrophication.

The aim of VALUES was to develop methods to describe the value and magnitude of these ecosystem services, to enable their integration in political decisions and in the end contribute to a sustainable management of the coastal zone.

Illustration of healthy and severely affected recruitment areas for fish. Dense stands of perfoliate pondweed with roach on the left and filamentous algae suffocating the underlying vegetation on the right. Photos: Göran Sundblad and Ulf Bergström.

Valuation and management of ecosystem services has come a long way since the Millennium Ecosystems Assessment (2005), but some key challenges remain. First, ecologists need a better understanding of the complexity of ecosystem production functions, their nonlinearities and interactions among multiple services, as well as of how to map these relationships and services at relevant spatial scales. Secondly, the value of ecosystem services must be explicitly and systematically integrated into decision making, policy and natural resource management at several levels of organisation. A fundamental challenge is also to understand how the value of ecosystem services may be affected by pressures from human activities. These challenges are particularly urgent in coastal areas of the world, including inland seas like the Baltic Sea, which contain some of the highest service values in the world, and where there is a severe risk of human pressure reducing the production of services.

The research project VALUES, financed by Swedish EPA, was carried out from 2014 to 2016. The background to the project was the need to for a better understanding of the complexity of ecosystem production functions, of how to map ecosystem services and how the value of ecosystem services can be integrated into decision making, policy and natural resource management. VALUES addressed these questions for two complementary types of underwater environments and their associated services, and dis-services, using a production function approach in a cross-disciplinary and integrated framework. Specific user-cases within VALUES, developed through collaboration with end-users and managers, provided concrete examples of how quantitative ecological understanding, together with economic valuation of services, can be successfully integrated at different levels of management.

VALUES was largely based on synthesizing recent research focused on mapping ecosystem production functions in relation to three human pressures; eutrophication, coastal development and invasive species. The value of ecosystem services provided by two separate but complementary study systems, shallow fish reproduction habitats and deep sediment habitats, were assessed. Through cross-disciplinary collaboration between experts on ecology and economy, VALUES i) developed a general framework that provides quantitative assessments of the value associated with services stemming from specific habitats under different human pressure levels, and ii) showed how coherent mapping of ecosystem service values in relation to impacts of major human activities can be successfully integrated in a long term sustainable management of the Baltic Sea. Mapping and valuation of the coastal environment is an important part of environmental objectives assessment as well as Habitats- and Marine Strategy Framework Directives reporting. The project increased the understanding of possibilities and limitations of using the value of marine ecosystem services in a management context.

Studies

The first study covered shallow, vegetated coastal habitats in the Baltic Sea. The coastal zone provides essential habitats for a large part of the economically most important fish species such as pike, perch and pikeperch. Of particular importance are shallow vegetated bays and lagoons, as availability to these habitat types have been shown to determine the production and sizes of fish populations. Several important ecosystem services are associated with the shallow vegetated bays functioning as fish reproduction areas. The habitat type provides food and opportunities for recreational fishing, while predatory fish dependent on the habitat type is important for ecosystem functioning through controlling growth of nuisance algae and indirectly habitat and water quality. Thus, these shallow sheltered bays constitute a habitat type maintaining a number of valuable ecosystem services, while at the same time being subject to several human pressures, as the dense human populations along the coasts put high, and accelerating, pressure on the coastal ecosystem through overexploitation, habitat transformation and pollution, threatening the valuable ecosystem services provided by these shallow-water habitats. A recent analysis shows that these habitats constituting fish reproduction areas are subject to heavy exploitation through shoreline construction, and that habitat degradation rates due to construction are accelerating. Simultaneously the reproduction habitats are highly affected by eutrophication. The effects of eutrophication on the habitats and indirectly on fish stock sizes are multifaceted, with some species losing and others actually gaining from the effects of eutrophication. The picture is further complicated by the fact that fishing, as an additional type pressure, may indirectly lead to a decrease in the quality of fish reproduction habitats by relaxing the top-down control of filamentous nuisance algae maintained by predatory fish.

The second study concerned aphotic soft substrate sediments, which cover approximately 90% of the Baltic Sea seafloor and provide crucial ecosystem functions such as decomposition of organic matter and re-mineralization of nutrients. Despite this, the importance of aphotic soft sediments in an ecosystem service context has largely been neglected, where previous studies in the Baltic Sea have mainly focused on near-shore ecosystem services. The human introduction of Marenzelleria, a polychaete genus, into the Baltic Sea has most likely changed crucial benthic processes that provide ecosystem services on a Baltic Sea-wide scale. Currently, knowledge on the large scale consequences of the Marenzelleria introduction on the Baltic Sea soft sediment ecosystem is severely lacking. By combining the quantification of biogeochemical processes in the presence or absence of Marenzelleria with high resolution maps of the modelled distribution of the species group in the Baltic Sea, its impact on nutrient cycling and release of contaminants can be quantified on a Baltic Sea scale. There are clear needs from a management perspective for data on the potential costs/values of marine non-indigenous species. This is both needed as examples of potential costs related to lack of preventive actions (there are no viable management options for a Baltic Sea wide Marenzelleria removal, but we can prevent introduction of additional species) and to meet the requirements of the EU Marine Strategy Framework Directive. Considering the potential large scale effects of Marenzelleria on Baltic Sea phosphorous, nitrogen and organic contaminant dynamics, this topic is also extremely relevant for fulfilling several international environmental commitments (HELCOM’s Baltic Sea Action Plan, EU Water Framework Directive) and national environmental objectives (particularly No Eutrophication and a Toxic-Free Environment).

Illustration of burrow systems of different soft bottom fauna species (Pontoporeia femorata, Monoporeia affinis, Macoma Balthica and Marenzelleria arctica). Image: Johan Näslund.

Project partners

AquaBiota Water Research (coordinator)
Swedish University of Agricultural Sciences – Institutions for Aquatic resources and Economy
The Baltic Sea Centre of Stockholm University
County Administrative Board of Stockholm

Press (in Swedish)

Scientific publications

Sundblad G., Bergström U., 2014: Shoreline development and degradation of coastal fish reproduction habitats. Ambio 43:1020-1028. DOI 10.1007/s13280-014-0522-y.
Sundblad G., Bergström U., Sandström A., Eklöv P., 2013: Nursery habitat availability limits adult stock sizes of predatory coastal fish. ICES Journal of Marine Science. DOI: 10.1093/icesjms/fst056, in press.

Reports

Gundersen H, Bryan T, Chen W, Moy F E, Sandman A N, Sundblad G, Schneider S, Andersen J H, Langaas S och Walday M G 2017: Ecosystem Services In the Coastal Zone of the Nordic Countries. TemaNord 2016:552. Nordiska Ministerrådet, Köpenhamn, 127 p.
Nyström Sandman. A., Bergström, U., Gren, I.-M., Sundblad, G., Tafesse Tirkaso, W. & Wikström, S. 2017: VALUES – Värdering av akvatiska livsmiljöers ekosystemtjänster. Naturvårdsverkets rapport 6752.